Elaborate measures are taken during the filming of motion pictures and the subsequent processing of prints thereof to produce products of the highest technical quality which the current state of the art allows. However, the film prints or films are vulnerable to a number of types of contaminants during handling and projection which can not only damage a given film and degrade the quality of the projected images thereof, but can also contaminate and damage components of the projector which can degrade the image quality of films subsequently shown on such a projector. The movement of the film base over components of film transport mechanisms in film processing and projection equipment can cause a buildup of static electricity on a film which attracts dust, lint, and the like. Additional contamination can come from lubricants within the film transport mechanisms.
The problem has long been recognized, and solutions have been proposed and implemented from the earliest days of the motion picture industry, with varying degrees of success. In one early film cleaning process, the film is transported past wicks moistened with grease solvents and afterwards past rotary brushes rotating in the opposite direction from film travel, prior to entry into a projector. In another process, the film is merely passed over rollers having cloth or felt surfaces. One problem with some of these types of film cleaning processes is that contaminants tend to build up on the cleaning media and can eventually be redeposited on the film or cause damage to the film base or emulsion thereon. In order to gradually change the cleaning surface in contact with the film strip, several process employ moving strips of cleaning fabric, past which the film is transported. Some products have been developed for neutralizing static electricity on the film strip by using a small amount of a radioactive material, such as polonium, in which radioactive decay of the material releases positively charged alpha particles to attract static electrons on the surface of the film. However, current environmental policies discourage the uncontrolled distribution of products incorporating radioactive substances.
A more modern approach involves transporting the film into contact with rollers coated with types of silicone putty to which dust, lint, greases, and other contaminants adhere. One problem with silicone putty is that it is in a semisolid state and is, thus, difficult to retain on the cleaning rollers. Current methods favor the use of a device referred to as a particle transfer roller which operates in a manner similar to the silicone putty rollers, but uses a compliant, but dimensionally stable, elastomer on an outer layer of the roller. Such rollers are manufactured by Eastman Kodak Company.
There is a limit to the amount of contaminants which the elastomeric particle transfer rollers can collect before the rollers become ineffective. However, the effectiveness of such rollers can be restored simply by washing the rollers in a mild soap, rinsing, and drying. What is needed is a film cleaner mechanism which enables the rollers to be conveniently removed for restoration of their film cleaning properties and conveniently reinstalled thereafter.